Paint spray booth detackification composition and method

ABSTRACT

Paint spray booth detackification compositions and methods are disclosed. The compositions comprise a hectorite clay, an anti-foaming agent and optionally, an aluminum oxide material and a montmorillonite clay. These compositions are introduced into a paint spray booth water wash system so as to detackify oversprayed paint.

FIELD OF THE INVENTION

This invention relates to an improved method and composition fortreating paint wastes and paint oversprays encountered in paint spraybooths or any areas where these wastes and oversprays exist.

BACKGROUND OF INVENTION

Spray painting of automobile bodies, truck engines, appliances, andother industrial goods is customarily carried out in enclosed areascalled paint spray booths (PSB). These booths act both to contain anyfumes or oversprayed paint and to reduce the chances of dustcontamination. These booths vary in size, but are somewhat basic intheir design and operation. A typical booth would thus consist of a workarea, back section with mist eliminators, and a sump.

The units to be painted generally pass through the work area while anairflow makes the oversprayed paint contact either the sump water or thespray from the water curtain. The air is scrubbed with recirculatedwater at the water curtain, passes through the mist eliminators, and isremoved by an exhaust fan.

Because roughly one-half of all paint sprayed does not reach itsintended article, a significant concentration of paint builds in thesystem and agglomeration can occur. The resultant mass is a sticky,tacky material which can plug the mist eliminators, shower heads, andeven recirculating pumps. When this happens, scrubbing efficiencydecreases leading to potentially hazardous conditions of unchecked paintemissions being discharged into the atmosphere. Such conditions may alsopresent severe safety hazards to paint spray booth operators.

This process involves other problems. These tacky organic deposits aresubject to bacterial growth and fungii proliferation which conditionsgenerate corrosion and odor problems. In addition, the paint solidswhich are recirculated can form suspensions in the water. They remaintacky and can create expensive separation and disposal problems.

These problems show, therefore, the desirability to treat PSB watersystems so as to reduce or prevent as much as possible, theagglomeration and deposition of oversprayed paint on critical PSBoperation parts; to render the resultant sludge non-tacky and easilyremovable; and to provide a water quality such that it can be recycledfor use in the system.

PRIOR ART

Many compositions and methods have been tried in an effort to reducethese problems. One of the first of these processes is disclosed in U.S.Pat. No. 2,585,407. This disclosure acknowledges the then conventionalpractice of allowing the overspray to come in contact with water treatedwith caustic to a pH above 8. The paint eventually settles by gravity tothe bottom of the sump where it is removed by shovelling the stickyresidue from the sump. This method eventually was consideredunacceptable and as a result, more sophisticated chemical treatmentshave been developed to separate the paint from the water and turn itinto a non-tacky, or detackified, solid which does not cause theaforementioned problems.

The prior art is replete with such chemical treatment approaches. Forinstance, the use of a combination of esters of aliphati dibasic acidsand bentonite clay is suggested in U.S. Pat. No. 2,362,964 (Affeck).Similarly, U.S. Pat. No. 3,515,575 (Arnold et al) discloses the use oftalc, chalk, starch, bentonite, clay, colloidal silica, calciumsilicate, magnesium silicate, aluminum silicate, antifoams in general,and polycationic or polyanionic polymers to perform the detackificationfunction.

Other prior art patents disclosing the use of bentonite clays in thisenvironment include U.S. Pat. Nos. 4,220,456 (Block); 2,267,426(Saunders et al); 4,185,970 (Dean); 4,125,476 (Dean); and 4,380,495(Maher).

Despite the advantages of the above-noted prior art approaches, thepresent inventors faced the problem of developing a versatiledetackification product and method capable of performing the intendeddetackification function for a wide degree of paint products includingwater based paints, oil based paints, lacquers, enamels and the newerhigh solids paints.

In addition to finding a versatile detackifier composition and method,the inventors attempted to develop a detackifier that remained suspendedin the wash water over a relatively long time period, in contrast tocertain of the prior art montmorillonite and bentonite clay detackifierswhich quickly separated from the wash water and hence could no longerfulfill the desirable detackifier function.

Of even further importance is the need for a detackification compositionand method capable of performing adequately with the difficult to "kill"epoxy, amino resin, vinyl resin based paints, alkyd resin, urethane andacrylic paints.

These and other problems have been substantially minimized by thecompositions and methods herein disclosed and claimed.

DETAILED DESCRIPTION

In accordance with the invention, it has been discovered that hectoriteclay effectively detackifies water-based paints, oil-based paints,lacquers and enamels.

Paint is a broad-based term used to describe the coating applied to agiven object. Paints are normally composed of a film former (the resinwhich forms the coating), a solvent or carrier (water or oil); pigments(for color), and additives such as biocides, drying agents, viscositymodifiers, etc. In general, the solvent is used to classify the painttype: either water base or oil base. Technically, if the paint forms itscoating by evaporation of the solvent without chemical reaction, it is alacquer. If the coating is formed via cross-linking, it is an enamel.

The term "clay" is unusual in that it has decidedly different meaningsto technologists in different fields. One standard definition for theterm is that of a "naturally occurring sediment (including that obtainedby alteration in situ by supergene and hydrothermal processes) orsedimentary rock composed of one or more minerals and accessorycompounds, the whole usually being rich in hydrated silicates ofaluminum, iron or magnesium, hydrated alumina, or iron oxide,predominating in particles of colloidal or near-colloidal size, andcommonly developing plasticity when sufficiently pulverized and wetted."Kirk-Othmer, Encyclopedia of Chemical Technology, Volume 5, page 544,(2nd edition) John Wiley and Sons, Inc., New York, N.Y. 1964.

The "montmorillonite" clays refer generically to crystalline clayshaving three layers. These clays are composed of units having two layersof silica tetrahedrons and one centrally disposed dioctahedral ortrioctahedral layer. Such montmorillonite clays may be classified aseither having an expanding lattice structure or a nonexpanding lattice.The Encyclopedia of Chemistry, (third edition), Van Nostrand ReinholdCo., New York, 1973.

The term "montmorillonite" has also been used to specify a speciesmember of the "montmorillonite" genus; i.e., an aluminous member of thegroup accorded the empirical formula ##STR1##

Both bentonite and hectorite are members of the expanding latticemontmorillonite subgenus. One difference between the two is that inhectorite, the aluminum present in the bentonite lattice is almostcompletely substituted by magnesium atoms. Another difference is thatlithium and fluorine are absent from the bentonite lattice and presentin the hectorite lattice. Bentonite may be characterized as a sodiumaluminum silicate, with hectorite being a sodium magnesium-fluoro-lithosilicate.

Hectorite has been given the empirical formula [Mg₂.67 Li₀.33(Na₀.33)]Si₄ O₁₀ (OH, F)₂.

One hectorite, which may be used in accordance with the invention isCapricorn H, Capricorn Chemicals. It has been reported to have thefollowing analysis:

    ______________________________________                                        Capricorn H                                                                   HECTORITE                                                                     ______________________________________                                        Shape:        Elongate                                                        Particle Size:                                                                              0.8 × 0.89 × 0.0010                                 (dispersed)   microns                                                         Type:         Trioctahedral                                                   Color:        White to Light Pink                                             Composition:                                                                  Clay           50.0%                                                          Water         6.1                                                             Quartz        1.0                                                             Cristobalite  --                                                              Calcite       30.0                                                            Dolomite      12.9                                                            Feldspar      --                                                              Gypsum        --                                                              Illite        --                                                                            100.0%                                                          Oxide Analyses:                                                               SiO.sub.2      55.86%                                                         Al.sub.2 O.sub.3                                                                             0.13                                                           Fe.sub.2 O.sub.3                                                                             0.03                                                           FeO           --                                                              MnO           None                                                            MgO           25.03                                                           CaO           Tr                                                              K.sub.2 O      0.10                                                           Na.sub.2 O     2.68                                                           Li.sub.2 O     1.05                                                           TiO.sub.2     None                                                            CO.sub.2      --                                                              F              5.96                                                           H.sub.2 O-     9.90                                                           H.sub.2 O+     2.24                                                                          102.98%                                                        ______________________________________                                    

In contrast, Wyoming bentonite has been reported to have the followinganalysis:

    ______________________________________                                        WYOMING BENTONITE                                                             ______________________________________                                        Shape:     Equidimensional                                                    Particle Size:                                                                           0.8 × 0.8 × 0.0010 microns                             (dispersed)                                                                   Type:      Dioctahedral                                                       Color:     Gray to Brown                                                      Composition:                                                                             Clay                77.4%                                                     Water              7.9                                                        Quartz             5.0                                                        Cristobalite       0.7                                                        Calcite            --                                                         Dolomite           --                                                         Feldsper           6.0                                                        Gyspsum            1.0                                                        Illite             2.0                                                                           100.0%                                          Oxide Analysis:                                                                          SiO.sub.2           55.44%                                                    Al.sub.2 O.sub.3   20.14                                                      Fe.sub.2 O.sub.3    3.67                                                      FeO                 0.30                                                      MnO                --                                                         MgO                 2.49                                                      CaO                 0.50                                                      K.sub.2 O           0.60                                                      Na.sub.2 O          2.75                                                      Li.sub.2 O         --                                                         TiO.sub.2           0.10                                                      CO.sub.2           --                                                         F                  --                                                         H.sub.2 O          14.70                                                                          100.69%                                        ______________________________________                                    

Other commercially available hectorite clays which may be used inaccordance with the invention include "Hectorite Clay" a naturalhectorite available from NL Industries; "Macoloid", a purified hectoriteavailable from NL Industries and "Bentone EW", a beneficiated hectoriteavailable from NL Industries.

By "natural" hectorite, we mean hectorite as it is mined. Typically such"natural" hectorite may comprise from around 40-60% hectorite and 40-60%other minerals.

Use of the phase purified hectorite in the disclosure and claimssignifies a hectorite which, via processing, has had all or most of thenon-clay components removed. This includes those hectorites which havebeen subjected to a drying step.

The phrase beneficiated hectorite is used herein to define hectoritesthat have been treated with or chemically reacted with organic or otherchemical treatments.

Of course, those skilled in the art may be capable of developing apurely synthetic hectorite. Such synthetic hectorites also fall withinthe ambit of the invention.

We have surprisingly found that use of the hectorite clays results ineffective paint detackification of many different paint types.Surprisingly, such hectorite clay detackifier products work much betterthan the prior art montmorillonites and bentonites. Although we do notintend to be bound by any particular theory of operation, it ispostulated that the enhanced detackification efficacy is caused by theremarkable expansion capacity exhibited by hectorites.

Moreover, hectorite is more versatile than the other clays mentionedabove in that it performs its detackification function with respect to awide variety of paint types, and is especially effective in detackifyingepoxy, polyurethane and vinyl resin paints which are difficult todetackify.

In combination with the hectorite clay, it is preferred to use anantifoaming agent such as a polyoxylkylene glycol or a silicone materialso as to minimize foaming problems that may occur. In order to providean effective yet inexpensive treatment, montmorilonite clays may becombined with the more expensive hectorite clay. Other materials such asalumina may also be added.

Compositions in accordance with the invention may comprise: (thepercentages adding up to 100%)

10-100 weight % hectorite clay

01-60 weight % montmorillonite clay (when present)

01-25 weight % alumina (when present)

01-5 weight % antifoam (when present)

At present, the composition preferred for use comprises:

68.2 weight % hectorite clay: (200 mesh): particle size--75 microns.

19.5 weight % montmorillonite clay

9.8 weight % aluminum oxide (325 mesh)

2.5 weight % antifoam

Prior to use, the composition is first preferably slurried with waterand then either shot or continuously fed to the spray system in anamount of about 0.5-50% by weight dry composition based on the weight ofthe oversprayed paint. The composition may also be added to the desiredpaint spray booth system in its dry powder form. Most preferably, thecomposition is added to the system at a rate of from about 1-15% byweight dry composition to weight oversprayed paint.

We have found that optimal results are attained when the dry compositionis subjected to high-shear agitation upon mixing with water. If suchhigh-shear agitation is not available, it is recommended that thecomposition be allowed to stand for about 24 hours after being mixedwith water. Also, it is beneficial if the water in the wash system ismaintained at or near a neutral pH (i.e., ≈6-8).

The following examples amply demonstrate that the compositions of thepresent invention may be successfully utilized in processes of the typewhich are directed toward the inhibition of pollution and/orcontamination in paint spray booth systems. In these types of water washsystems, the water is used to wash air in the booth and to removeoversprayed paints, enamels or lacquers. Solids may be removed byconventional techniques via filters, etc. The water is normallyrecirculated so that it may once again perform its intended washingfunction. Upon treatment with the detackification compositions of theinvention, the tackiness of the paints, enamels and lacquers is reducedand therefore, to the extent that these paints, enamels and lacquers arenot separated from the liquid phase, they exhibit less tendency toadhere to the integral parts of the pumps, mist eliminators or sumpsidewalls of the spray booths. Further, the agglomeration function ofthe detackification compositions facilitates removal of these wastepaint solids from the water so that relatively clean water can berecirculated in the system. Another important function of the treatmentof the present invention is to reduce the volume of the resultantsludge.

The detackification compositions (based upon the weight of oversprayedpaint) can be admitted in the paint spray booth system at variedlocations including; the sump, upstream from pumps, or at anyadvantageous position along the circulating water system.

The invention will now be further described with reference to a numberof specific examples which are to be regarded solely as illustrative andnot as restricting the scope of the invention.

SPECIFIC EMBODIMENTS Example 1

In order to access the effectiveness of hectorite clays in detackifyingpaints, each of the clays listed below was prepared as a 5% weightsolution in water. Then, 2 cc of each 5% clay solution were mixed with98 cc water and 1 cc of the test paint in a jar. After this addition,the resulting mixture was agitated and then allowed to settle. Theoverall resulting water clarity was judged subjectively, andobservations were made as to whether the paint coated the glass jar, thecharacteristics of the floc formed, and the approximate ratio of sunk tofloating paint. Results are recorded in Tables IA and IB hereinbelow.

                  TABLE IA                                                        ______________________________________                                        High Solids White Paint - styrene/melamine/                                   acrylate binder, ketone/alcohol/acetate solvent                                      Jar Test Results                                                       Clay             Coated  % Sink/                                              Additive Floc    Glass   Float  Comments                                                                              Rating                                ______________________________________                                        montmoril-                                                                             oily    yes     10/90  globby  fair                                  lonite   N-C                    beads                                         montmoril-                                                                             oily    yes     70/30  globby  poor                                  lonite/  cont                                                                 calcium                                                                       carbonate                                                                     sodium mont-                                                                           oily    yes     65/35  small globs                                                                           poor                                  morillonite                                                                            N-C                                                                  sodium mont-                                                                           small,  Yes     60/40  small floc                                                                            fair                                  morillonite                                                                            oily                                                                 sodium mont-                                                                           med,    Yes     50/50  medium  fair                                  morillonite                                                                            oily                   floc                                          sodium mont-                                                                           NC      yes     50/50  globby  poor                                  morillonite                                                                   purified fluffy  no      20/80  excellent                                                                             excellent                             hectorite                       kill                                          modified sticky  yes     --     globby, bad                                   organo clay                     unkilled                                      modified sticky  yes     60/40  unkilled                                                                              poor                                  organo clay                                                                   kaolin   oily,   yes            non-tacky                                                                             fair                                           N-C                                                                  hectorite                                                                              fluffy  no      20/80  excellent                                                                             excellent                                                             kill                                          western  small   yes     20/80  small paint                                                                           good                                  bentonite                                                                              beads                  beads                                                                         in flocs                                      western  small   yes     40/60  small paint                                                                           good                                  bentonite                                                                              beads                  beads                                                                         in flocs                                      western  small   yes     40/60  small beads                                                                           good                                  bentonite                                                                              beads                  in floc                                       crude kaolin                                                                           globby  yes     --     unkilled                                                                              poor                                  kaolin,  globby  yes     30/70  unkilled                                                                              poor                                  ceramic,                                                                      grade                                                                         control  globby  yes     --     unkilled                                                                              poor                                  ______________________________________                                         N-C means a noncontinuous layer of paint                                      Cont. means a continuous layer of paint                                       % sink/float relates to the floc layer                                   

                  TABLE IB                                                        ______________________________________                                        Blue Lacquer Paint - methacrylate binder,                                     ester/mixed aromatic solvent -                                                         Jar Test Results                                                     Clay             Coated  Sink/                                                Additive Floc    Glass   Float  Comments                                                                              Rating                                ______________________________________                                        montmoril-                                                                             small   no      0/100  fluffy, good                                  lonite                          small flocs                                   montmoril-                                                                             beady,  yes     5/95   globby, poor                                  lonite/  cont                   oily                                          calcium                                                                       carbonate                                                                     sodium mont-                                                                           fluffy  no      0/100  small,  good                                  morillonite                     fluffy floc                                   sodium mont-                                                                           fluffy  no      0/100  small,  v. good                               morillonite                     fluffy floc                                   sodium mont-                                                                           small   no      0/100  moderate                                                                              good                                  morillonite                     foam                                          sodium mont-                                                                           fluffy  yes     0/100  moderate                                                                              good                                  morillonite                     foam                                          purified fluffy  no      0/100  small,  excellent                             hectorite                       fluffy floc                                   modified globby  yes     --     all paint                                                                             v. bad                                organo-clay                     stuck to                                                                      glass                                         modified beady   no      0/100  continuous                                                                            fair                                  organo-clay                     layer                                         Kaolinite                                                                              beady-  no      10/90  non-    good                                           N-C                    continuous                                                                    layer                                         hectorite                                                                              fluffy  no      0/100  wide floc                                                                             excellent                                                             layer                                         western          no      2/98   clay/paint                                                                            good                                  bentonite                       separation                                    western  small   no      0/100  fluffy, good                                  bentonite        no      20/80  small clay/                                                                           good                                                                  paint                                                                         separation                                    western  globby, no      5/95   small globs                                                                           fair                                  bentonite                                                                              cont                                                                 crude kaolin                                                                           beady   yes            unkilled,                                                                             poor                                                                  cont.                                         kaolin   beads   yes     0/100  oily,   poor                                  ceramic                         continuous                                    grade                                                                         control  globby  yes     0/100  oily,   poor                                                                  continuous                                    ______________________________________                                    

Example 2

Another series of jar tests was performed with the clays, talcs,zeolites and silicates listed below being used as detackifying agents.The procedure used in Example 1 was repeated. This time, however,foaming propensity was measured on a subjective 1 to 5 scale with #1signifying worse than control, #2 signifying control, and #5 indicatinga lack of foam formation. Floc depth was measured (in milliliters) asopposed to the subjective sink/float ratio used in Example I. Inaddition to the other subjective characteristics measured in conjunctionwith Example 1, a "finger test" was performed in which the tester'sfinger was placed in the formed floc and then visual and tactileobservations recorded. All results appear in Tables IIA-C. As usedherein, Composition "A" refers to a composition consisting of 68.2weight % hectorite, 19.5 weight % montmorillonite, 9.8 weight % aluminumoxide, and 2.5% polyoxylalkylene glycol antifoam.

                  TABLE IIA                                                       ______________________________________                                        BROWN PAINT - melamine modified alkyd binder,                                 ethylene glycol monoethylether acetate solvent                                                           Float        Coating                               Detackifying                                                                           Floc              Sink  Finger on                                    Agent    Description                                                                             Foam    (MM)  Test   Jar                                   ______________________________________                                        Composition                                                                            Fluffy,   1        5/11 oily,  None                                  "A"      small beads             smears                                                                        non-                                                                          tacky                                        natural  Fluffy,   1       12/18 oily,  None                                  hectorite                                                                              small beads             smears                                                                        non-                                                                          tacky                                        purified Fluffy,   1       11/34 Oily,  None                                  hectorite                                                                              small beads             smears                                                                        non-                                                                          tacky                                        modified Oily, con-                                                                              5       2/0   Greasy None                                  organo-clay                                                                            tinuous                 non-                                                                          tacky                                        beneficiated                                                                           Fluffy,   1       18/25 Slightly                                                                             None                                  hectorite                                                                              small beads             rollable                                     modified Globby,   5       --/-- Not    Yes                                   organo-clay                                                                            non-                    killed                                                continuous                                                           modified Globby,   5       --/-- Not    Yes                                   organo-clay                                                                            non-                    killed                                                continuous                                                           modified Globby,   5       --/-- Not    Yes                                   organo-clay                                                                            non-                    killed                                                continuous                                                           sodium   Oily, con-                                                                              5       2/0   Smears Yes                                   silicon  tinuous                                                              aluminate                                                                     hydrated Oily, con-                                                                              5       2/1   Smears Yes                                   silicon  tinuous                                                              dioxide                                                                       attapulgite                                                                            Fine,     5       Beady Unkilled                                                                             Minimal                               clay     beady,            layer/3                                                     continuous                                                           attapulgite                                                                            Oily,     5       --/thin                                                                             Unkilled                                                                             Con-                                  clay     globby,           layer        tinuous                                        non-                                                                          continuous                                                           talc     Small     4       2/1   Oily   Yes                                            beady &                                                                       flaky                                                                talc     Medium    4       2/1   Oily   Yes                                            beady floc                                                           talc     Beady     5       2/1   Oily   No                                                                     layer on                                                                      bottom                                       talc     Beady     5       2/1   Oily   No                                                                     layer on                                                                      bottom                                       zeolite sieve                                                                          Oily, non-                                                                              5       1/1   Dis-   Yes                                            continuous              persion                                      zeolite sieve                                                                          Oily, non-                                                                              5       1/1   Dis-   Yes                                            continuous              persion                                      zeolite  Oily, non-                                                                              5       0/2   Dis-   Yes                                            continuous              persed                                       zeolite  Oily, non-                                                                              5       0/2   Dis-   Yes                                            continuous              persed                                       hollow,  Continuous,                                                                             5       2/0   Heavy  Yes                                   inorganic                                                                              globby                  coating                                      microsphere                                                                   hollow,  Continuous,                                                                             5       2/0   Heavy  Yes                                   inorganic                                                                              globby                  coating                                      microsphere                                                                   hollow,  Continuous,                                                                             5       3/0   Heavy  Yes                                   inorganic                                                                              globby                  coating                                      microsphere                                                                   activated                                                                              Medium    5       0/2   Dis-   Yes                                   bauxite  beady floc              persion                                      ______________________________________                                    

                  TABLE IIB                                                       ______________________________________                                        RED/BROWN PRIMER - melamine modified epoxy binder,                            alcohol/acetate/mixed aromatics solvent                                                                  Float        Coating                               Detackifying                                                                           Floc              Sink  Finger on                                    Agent    Description                                                                             Foam    (MM)  Test   Jar                                   ______________________________________                                        Composition                                                                            Fluffy, tiny                                                                            1       9/2   Smears,                                                                              No                                    "A"      beads in                non-                                                  floc                    tacky                                        hectorite                                                                              Fluffy, tiny                                                                            1       10/2  Smears, No                                            beads in                non-                                                  floc                    tacky                                        purified Fluffy, tiny                                                                            1       20/3  Rollable                                                                             No                                    hectorite                                                                              beads in                                                                      floc                                                                 modified Beady,    5       4/1   Greasy,                                                                              Yes                                   organo-clay                                                                            flaky flocs             non-                                                                          tacky                                        beneficiated                                                                           Fluffy, tiny                                                                            1       22/2  Rollable,                                                                            No                                    hectorite                                                                              beads in                non-                                                  floc                    tacky                                        modified Globby,   5       --/-- Tacky  Yes                                   organo-clay                                                                            non-                                                                          continuous                                                           modified Globby,   5       --/-- Tacky  Yes                                   organo-clay                                                                            non-                                                                          continuous                                                           modified Small     5       --/-- Tacky  Yes                                   organo-clay                                                                            globs,                                                                        non-                                                                          continuous                                                           sodium   Beady, con-                                                                             5       2/1   Oily   Yes                                   silicon  tinuous                                                              aluminate                                                                     hydrated Beady     4       3/1   Oily   Yes                                   silicon                                                                       dioxide                                                                       talc     Fluffy floc                                                                             4       3/2   Oily   Slight                                talc     Fluffy floc                                                                             4       3/1   Oily   Non-con-                                                                      tinuous                               talc     Globby    5       3/1   Oily   Yes                                            continuous                                                           talc     Globby    5       3/1   Oily   Yes                                            continuous                                                           zeolite sieve                                                                          Beady &   5       1/1   --     Yes                                            globby                                                               zeolite sieve                                                                          Tiny beads                                                                              5       1/1   --     Yes                                            & globby                                                             zeolite  Beady, con-                                                                             5       2/0   Globby,                                                                              Yes                                            tinuous                 smears                                       zeolite  Beady, con-                                                                             5       2/0          Yes                                            tinuous                                                              hollow,  Beady,    5       2/0   Greasy Yes                                   inorganic                                                                              globby                                                               microsphere                                                                   hollow,  Beady,    5       2/1   Greasy                                       inorganic                                                                              globby                                                               microsphere                                                                   hollow,  Beady,    5       2/1   Greasy                                       inorganic                                                                              globby                                                               microsphere                                                                   activated                                                                              Beady,    5       1/1   Oily   Yes                                   bauxite  globby                  layer on                                                                      bottom                                       ______________________________________                                    

                  TABLE IIC                                                       ______________________________________                                        CAMEL TAN - melamine modified alkyd/styrene binder,                           ethylene glycol monethyl ether acetate/mixed aromatics solvent                                                         Coat-                                                           Float         ing                                           Floc      Foam    Sink          on                                   Adsorbant                                                                              Description                                                                             (1-5)   (MM)  Class II                                                                              Jar                                  ______________________________________                                        Composition                                                                            Fluffy with                                                                             1        3/38 Oily, coats                                                                           No                                   "A"      tiny beads              finger, non-                                                                  tacky                                        hectorite                                                                              Fluffy with                                                                             1        3/20 Oily, coats                                                                           No                                            tiny beads              finger, non-                                                                  tacky                                        purified Fluffy with                                                                             1        7/55 Non-tacky,                                                                            No                                   hectorite                                                                              tiny beads              light                                                                         coating                                      modified Continuous                                                                              5       --/-- Coats   Yes                                  organo-clay                                                                            with some               finger,                                               beads                   non-tacky                                    beneficiated                                                                           Fluffy with                                                                             1       22/32 Non-tacky,                                                                            No                                   hectorite                                                                              tiny beads              light                                                                         coating                                      modified Oily,     5       1/0   Oily, non-                                                                            Yes                                  organo-clay                                                                            globby,                 tacky                                                 non-                                                                          continuous                                                           modified Oily,     5       1/0   Oily, non-                                                                            Yes                                  organo-clay                                                                            globby,                 tacky                                                 non-                                                                          continuous                                                           modified Beady,    5       2/0   Oily, non-                                                                            Yes                                  organo-clay                                                                            flaking                 tacky                                        attapulgite                                                                            Oily, non-                                                                              5       --/-- Oily, non-                                                                            Yes                                  clay     continuous              tacky                                        attapulgite                                                                            Oily, non-                                                                              5       --/-- Oily, non-                                                                            Yes                                  clay     continuous              tacky                                        ______________________________________                                    

Discussion Tables I and II

The hectorite clays are clearly the best paint detackifiers/dispersantsof the materials evaluated. The montmorillonite clays were somewhatefffective, but not nearly as effective as the hectorite clays. All ofthe other tested products were ineffective.

Quite surprisingly, the hectorite products appeared to work well on allof the paint samples tested. It is noted that all of the testedhectorite samples exhibited a tendency to foam. Hence, Composition "A"was developed so as to formulate a hectorite based detackifier with anantifoam component.

Example 3

In order to ascertain the detackification efficacy of the antiforamcontaining hectorite product, another series of jar tests, as perExamples 1 and 2, was undertaken. This time, the hectorite product wascompared to other commercially available, well-known detackifierproducts. Results are shown in Tables IIIA-C.

                                      TABLE IIIA                                  __________________________________________________________________________    Red/Brown Primer - melamine modified epoxy                                    binder, alcohol/acetate/mixed aromatics solvent                                         Coating                                                                            Floc                                                                              Floc          Treatment                                    Product/  on   Depth                                                                             Descrip-                                                                             Finger Rating (per                                  Paint Foam*                                                                             Jar* (mm)                                                                              tion   Test   paint)                                       __________________________________________________________________________    Composi-                                                                            3   5    4   fluffy floc,                                                                         light coat,                                                                          good, best                                   tion "A"       no beads of                                                                       slight tack,                                                                         overall                                                                paint, easily                                                                        not oily,                                                              disperses,                                                                           does not                                                               medium floc                                                                          smear                                               montmoril-                                                                          4   5    2   very fine                                                                            light coat,                                                                          good                                         lonite             floc, easily                                                                         slight tack,                                                           disperses,                                                                           not oily,                                                              unused clay                                                                          does not                                                               on bottom                                                                            smear                                               montmoril-                                                                          5   3    4   medium floc                                                                          heavy coat,                                                                          poor                                         lonite/            with chunks                                                                          smears on                                           calcium            of paint                                                                             glass                                               carbonate                                                                     diatoma-                                                                            5   4    2   medium floc                                                                          medium coat,                                                                         fair                                         ceous              with chunks                                                                          oily, tacky                                         earth              of paint                                                   Control                                                                             5   2    0   chunky, un-                                                                          oily, heavy                                                                          poor                                                            killed coat, un-                                                                     killed                                              __________________________________________________________________________

                                      TABLE IIIB                                  __________________________________________________________________________    Silver - acrylic modified polyester                                           binder, alcohol/acetate/acetone solvent                                                 Coating                                                                            Floc                                                                              Floc          Treatment                                    Product/  on   Depth                                                                             Descrip-                                                                             Finger Rating (per                                  Paint Foam*                                                                             Jar* (mm)                                                                              tion   Test   paint)                                       __________________________________________________________________________    Composi-                                                                            4   5    13  fluffy, easi-                                                                        light coat-                                                                          good-                                        tion "A"           ly disperses,                                                                        ing on fin-                                                                          best                                                            fine particle                                                                        ger, no                                                                              overall                                                         size, small                                                                          smear on                                                               beads of                                                                             glass, oily                                                            paint in floc                                              montmoril-                                                                          5   5    3   floc easily                                                                          medium coat                                                                          good                                         lonite             disperses,                                                                           on finger,                                                             medium size                                                                          oily                                                                   floc                                                       montmoril-                                                                          5   3    0   terrible,                                                                            unkilled,                                                                            bad                                          lonite             chunks of                                                                            oily, tacky                                                            paint on                                                                      bottom                                                     diatoma-                                                                            5   4    1   medium flocs                                                                         unkilled,                                                                            poor                                         ceous              with chunks                                                                          oily, tacky                                         earth              of paint                                                   Control                                                                             5   1    0   continuous                                                                           unkilled,                                                                            bad                                                             layer                                                      __________________________________________________________________________

                                      TABLE IIIC                                  __________________________________________________________________________    GREY PRIMER (high solids)                                                               Coating                                                                            Floc                                                                              Floc          Treatment                                    Product/  on   Depth                                                                             Descrip-                                                                             Finger Rating (per                                  Paint Foam*                                                                             Jar* (mm)                                                                              tion   Test   paint)                                       __________________________________________________________________________    Composi-                                                                            4   5    11  fluffy, easi-                                                                        light coat                                                                           good-                                        tion "A"           ly disperses,                                                                        on finger,                                                                           best                                                            fine particle                                                                        not oily,                                                                            results -    size, small no smear                               beads of                                                                      paint in floc                                              montmoril-                                                                          4   5    4   medium size                                                                          medium coat,                                                                         good                                         lonite             floc with                                                                            not oily,                                                              large beads                                                                          smeared on                                                             of paint,                                                                            jar                                                                    cloudy H.sub.2 O                                           montmoril-                                                                          5   3    0   chunks of                                                                            greasy,                                                                              poor                                         lonite/            paint float-                                                                         heavy coat                                          calcium            ing                                                        carbonate                                                                     diatoma-                                                                            5   4    2   beads of                                                                             oily, un-                                                                            fair                                         ceous              paint, no                                                                            killed, not                                         earth              real flocs                                                                           tacky                                               Control                                                                             5   3    0   continuous                                                                           greasy, not                                                                          poor                                                            glob on                                                                              killed                                                                 bottom                                                     __________________________________________________________________________     *Rating as follows: 0 = very heavy; 5 = none at all. All numbers in           between represent degrees of 0 to 5.                                     

It is apparent from the examples that the hectorite detackificationagents of the invention provide excellent results in conjunction with avariety of differing paint types.

In accordance with the patent statutes, the best mode of practicing theinvention has been herein set forth. However, it will be apparent tothose skilled in the art that many modifications can be made withoutdeparting from the spirit of the invention. It is to be understood thatthe scope of the invention is to be limited solely by the scope of theappended claims.

We claim:
 1. A process for controlling pollution and contamination in paint, lacquer or enamel spray booths in which water is used to wash air in said booth and to remove over-sprayed paints, enamels or lacquers, said water being recirculated for further use in washing the air in said spray booths, said process comprising adding to said water an effective amount for the purpose of a detackifying composition consisting essentially of a hectorite clay having the empirical formula [Mg₂.67 Li₀.33 (Na₀.33)]Si₄ O₁₀ (OH,F)₂, said amount being sufficient to reduce the tackiness of said paints, enamels and lacquers and to thereby reduce the tendency of oversprayed paints, enamels and lacquers to adhere to pump parts, mist eliminators, or sump sidewalls of said spray booths, said composition being effective to condition paint, enamel and lacquer solids so as to facilitate removal of said solids from said water.
 2. Process as recited in claim 1 wherein said composition is added to said water at a rate of between about 0.5-50% by weight based upon the weight of said over-sprayed paint, enamel or lacquer.
 3. Process as recited in claim 2 wherein said composition is added to said water at a rate of between about 1-15% by weight based upon the weight of said over-sprayed paint, enamel or lacquer.
 4. Process as recited in claim 1 wherein said hectorite clay is a member selected from the group consisting of natural hectorite clay, purified hectorite clay, beneficiated hectorite clay synthetic hectorite clay and mixtures thereof. 